1. Field of the Invention
The present invention relates to the preparation of acrylamide or methacrylamide by reacting acrylonitrile or methacrylonitrile with water in the presence of a metallic copper containing catalyst.
2. Description of the Prior Art
U.S. Pat. No. 3,381,034 teaches that cuprous ions catalyze the hydrolysis of nitriles and discloses that such ions may be provided by a cupric salt and copper metal. Metallic cooper alone was disclosed and exemplified to have no catalytic effect in the process, although the patentees could not explain tha advantages of the presence of copper metal when the cuprous ion was present. Reaction times on the order of 20 hours were usually necessary to obtain a conversion greater than 25 mol percent based on the nitrile.
It is known that acrylamide or methacrylamide may be prepared from acrylonitrile or methacrylonitrile in the presence of a copper metal catalyst. The copper catalysts suitable for the process include Raney copper, Ullmann copper, reduced copper, and copper catalysts containing metallic nickel, chromium, manganese, zinc, or molybdenum as well as oxides and sulfides of these metals or such catalysts supported on carriers (U.S. patent application Ser. No. 56,967, filed on July 21, 1970 owned by the assignee of the present application).
When acrylonitrile or methacrylonitrile is hydrated using one of the aforementioned catalysts, a reaction for producing acrylamide can be carried out in the presence of a very small amount of the copper catalyst, for example, about 0.01 g. of the copper catalyst based on 1 mol of acrylonitrile. However, a high conversion is not obtained, and in order to adopt this as an industrial process, a more effective catalyst system is desired.